**Question:** Measles vaccination is given at the age of

A. 6 months
B. 9 months
C. 12 months
D. 18 months

**Core Concept:** Measles is a highly contagious viral disease caused by the measles virus. Vaccination is an effective way to prevent measles and is typically administered within the Expanded Programme on Immunization (EPI) schedule.

**Why the Correct Answer is Right:** The measles vaccine, which is a combination of vaccines for measles, mumps, and rubella (MMR), is typically administered as part of the EPI schedule. The correct answer, D (18 months), refers to the second dose of the MMR vaccine, which is typically given between 12 and 15 months of age. This is because the immune system needs time to mature and develop enough to effectively respond to the vaccine.

**Why Each Wrong Option is Incorrect:**

A (6 months): The first dose of the MMR vaccine is typically given between 12-15 months of age. Administering the vaccine too early may lead to an inadequate immune response due to the child's immature immune system.

B (9 months): Similar to option A, administering the vaccine too early may result in an inadequate immune response. Additionally, it is generally recommended to wait until the child has completed their first 6 months of life before starting any vaccinations.

C (12 months): While this is a close answer, administering the vaccine at this age is still too early. The immune system needs time to mature, and the first dose should ideally be given between 12-15 months of age.

**Clinical Pearl:** The optimal timing of vaccinations is crucial to ensure an effective immune response and is determined based on the child's age and overall health status. Always consult with a healthcare professional before administering any vaccinations to a child.

**Correct Answer:** D (18 months)

The second dose of the MMR vaccine is typically administered between 12 and 15 months of age to ensure an adequate immune response. This dose is often referred to as the "booster dose" or "second dose." The MMR vaccine provides lifelong immunity against measles, mumps, and rubella, reducing the risk of these serious infections in children and adults.